: Each year, thousands of migrant farm workers migrate to the Pacific Northwest to harvest berry crops. A great number of these laborers are adolescents--some traveling alone and others working alongside their families in the agricultural fields. These adolescents are exposed to pesticide spray (drift) and residues in the soil and on foliage. However, little scientific evidence is available to determine acceptable levels of pesticide exposure in this vulnerable population. Pesticides are thought to pose a considerably higher biological risk to children than to adults, but little is known about the extent or magnitude of this vulnerability. The potential of neurotoxicity related to chronic low-dose pesticide exposure in children is a major public health concern. Also, there may be risk factors that influence the occupational exposures of youth agricultural workers, and the period of rapid development during adolescence may introduce added risk in areas such as DNA damage related to pesticide exposure. Our interdisciplinary research team will use a cross-sectional, repeated measures design to compare adolescent farmworkers to their adult counterparts and to non-agricultural referent groups in order to: 1) determine differences in exposure to agricultural chemicals with urinary biomarkers of pesticide metabolites, 2) examine the relationship between urinary pesticide metabolites and neurobehavioral performance, and 3) determine age-related differences in pesticide-induced markers of DNA damage and oxidative stress.